document.write( "Question 495284: I have 8 runners in a race...what is the probability that i will pick 1, 2 and 3rd place \n" ); document.write( "
Algebra.Com's Answer #336055 by Theo(13342)![]() ![]() You can put this solution on YOUR website! the probability you will pick the winner is 1/8 \n" ); document.write( "if you are so lucky to pick the winner, the probability you will pick second place runner is 1/7. \n" ); document.write( "if you are so lucky to pick second place, the probability you will pick third place is 1/6. \n" ); document.write( "the probability you will pick all 3 is 1/8 * 1/7 * 1/6 = 1/336. \n" ); document.write( "you might be able to see this easier if we had only 3 runners and we had to pick the first and second place finish. \n" ); document.write( "assume the runners are a, b, and c \n" ); document.write( "the probability you will pick the winner is 1 out of 3. \n" ); document.write( "the possible finishes are: \n" ); document.write( "abc \n" ); document.write( "acb \n" ); document.write( "bac \n" ); document.write( "bca \n" ); document.write( "cab \n" ); document.write( "cba \n" ); document.write( "you can see that: \n" ); document.write( "a finishes first in 2 out of the 6 possible permutations. \n" ); document.write( "b finishes first in 2 out of the 6 possible permutations. \n" ); document.write( "c finishes first in 2 out of the 6 possible permutations. \n" ); document.write( "the probability of any one of them finishing first is 2 out of 6 which is equal to 1/3. \n" ); document.write( "now, suppose you picked a, and a was in first place. \n" ); document.write( "that leave b and c to finish second or third. \n" ); document.write( "the possible permutations are now: \n" ); document.write( "bc \n" ); document.write( "cb \n" ); document.write( "that means that: \n" ); document.write( "b finishes second in 1 out of the 3 possible permutations. \n" ); document.write( "c finishes second in 1 out of the 3 possible permutations. \n" ); document.write( "the probability of any one of them finishing second is 1 out of 2 which is equal to 1/2. \n" ); document.write( "the probability of both occurrences happening is 1/3 * 1/2 = 1/6. \n" ); document.write( "look at all 6 possible permutations again. \n" ); document.write( "abc \n" ); document.write( "acb \n" ); document.write( "bac \n" ); document.write( "bca \n" ); document.write( "cab \n" ); document.write( "cba \n" ); document.write( "you pick a to be the winner and b to be second. \n" ); document.write( "a is the winner and b is second in only 1 out of the 6 possible permutations. \n" ); document.write( "that's your answer. \n" ); document.write( "the probability is 1 out of 6. \n" ); document.write( "in your problem, the number of runners is 8 and you are trying to pick the first 3 winners. \n" ); document.write( "p(first) is 1/8 \n" ); document.write( "p(second) is 1/7 \n" ); document.write( "p(third) is 1/6 \n" ); document.write( "p(all three) is 1/8 * 1/7 * 1/6 = 1/336 \n" ); document.write( "same thing only more runners to choose from so it's a lot harder to show you how it works.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |